Improvement in pneumatic motors



GEORGE H. REYNOLDS,

UNITED STATES PATENT OFFICE.

OF NEVVYORK, N. Y., AND HERMAN HAUPT, OF

PHILADELPHIA, PA.

IMPROVEMENT IN PNEUMATIC MOTORS.

Specification forming part of Letters Patent No. 922,950, dated December23,1879; application filed March 26, 1879.

To all whom at may concern- Be it known that we, GEORGE H. REY- NOLDS,of the city and State of New York, and HERMAN HAUPT, of the cityandcounty of Philadelphia, in the State of Pennsylvania, have inventedcertain new and useful Improvements in Pneumatic Motors, of which thefollowing is a full, clear, and exact description, reference being hadto the accom panyingdrawings, forming part of the same. 1

This invention relates to the use of compressed air as a motive agent,and although applicable to motors for various purposes is moreespecially designed to be used for driving locomotive enginesorcarriages on tramways and other roads.

In the use of compressed air as a motive power for locomotive purposesit is desirable, on account of the limit of reservoir-capacity, to usethe air at the highest practicable initial pressure.

The use of the air at such high pressure has been attended with greatdifiiculties, one of which is the liability to congelation of moistwe onthe surfaces of the engine, resulting from the low temperatureconsequent upon the high rate of expansion.

Another difliculty results from the excessive pressure upon the valves,which renders them liable to cut; and a further one is that, owing tothe necessity of cutting 0E very early in the stroke of the piston, thefull initial pressure is exerted on the engine-crank only while it is inits least efl'ective position-via, when it is at or very near itsdead-center.

The first-mentioned difliculty hasbeen partially overcome by heating theair before introducing it to the enginecylinder; but when this has been.done an engine of the sim le type has always been used.

The object of our invention is to further overcome the severaldifficulties above mentioned; and to this end we employ an engine of thecompound type, andthough we may or may not heat the air before itsintroduction to the engine we always heat it after its exhaust from thehigh-pressure cylinder and before its induction to the low pressurecylinder; and to this end our invention consists in the combination,with a compound engine for the use of compressed air for motive power,of a heater placed between itshigh and low pressure cylinders andcontaining heated water or other liquid, through or in contact withwhich the air passes between its eduction from the one cylinder and itsinduction into the other.

In the application of the invention to 1000- motives or locomotive-carsthis heater may occupy any convenient position on or under thelocomotive or car, and may be filled with hot water, or such other hotliquid as it may be desirable to use, from a "stationary boiler orheater suitably placedat the terminus or other 0011- venient place nearthe track".

In other applications of our invention the said heater may be suppliedwith heated water or other liquid in .any convenient manner.

Referring to the accompanying drawings, Figure 1 represents a sectionalplan of a compressed-air locomotive-engine in part having the inventionapplied, and Fig. 2 ,a transverse section thereof through the workingcylinders of the engine.

A represents the framing of the locomotive,

which may be. of any suitable construction, and

B B its running and drivingwheels. G is the smaller cylinder, and D thelarger cylinder, of a compound engine used to propel the locomotive orcarriage, and the pistons a b of which are respectively connected bysuitable rods with cranks c d on the driving-shaft E.

G G are compressed-air reservoirs,of which there-may be any suitablenumber carried by the locomotive, and which may be-charged or rechargedwith compressed air under a high pressure at the termini or anyintermediate places on the road. The air from these reservoirs is firstconducted by pipesle to a heater, H, which may be termed a ihighpressureheater, and from thence, by a pipe, f, to the highpressure or smallercylinder 0 of the compound engine, subject,- of course, to the controlof a suitable valve applied to said cylinder. After the air hasperformed its duty in the hi gh-pressure cylinder 0 it is exhaustedtherefrom and passed, by a pipe, 9, to a heater, H, which may be termedthe low-pressure heater, and from whence it is passed. bv a pipe, h, tothe valve-box of" the larger or low pressure cylinder I), there to doits duty by expansion, and ultimately'escape to the atmosphere by apipe, 1'.

The low-pressure heater-H, which is the prrncipaltfcature of thecombination which constitutes our invention, may be of anysuitablehonstruction capable of .sustalning the pressure due to the heatof the water or other liquid with which it is to be charged for the jcylinder D, and should have suitable provision afforded by its form orconstruction for the air introduced into it from the one cylinder topass through or in extensive surface-contact with the, hot water orother liquid contained therein before its advent to the low-pressurecylinder, The higlrpressure heater may he of similar construction.

The air in passing through or in contact with the hot liquid in theheater H, may have its expansive force very con siderablyincreased bythe heat which it takes up from the liquid, while there is a verygradual reduction of the temperature. This is'owing to the differencebetween the specific-heat'of the air and of the liquid. When the liquidusediu the heater H is water a very considerable increment of. expansive force is obtained from the vapor which is' taken up by andmixedwvit'h the air.

By means of the compound engine air at a very 'igh pressure in the.reservoir ma be used without employing a reducer, and Without much orany cutting of the valves, and without cutting ofi dis-advantageouslyearly in the stroke, by reason of the piston of the highpressurecylinder being exposed on its exhaust side to the working pressure oftheair in the larger or low-pressure cylinder.

4 The number of heaters interposed between the cylinders may be varied,and, if' desired, the air from the reservoirs may be passed direct fromthe latter to the first, or high-pressure; cylinder-without circulatingit through a heater; but'it'is preferred to use heaters for warming,expanding, and keeping up the pressore of the air in the transmission ofit to the high' pressure cylinder as well-as to'the' lowpressurecylinder," thus obtaining the advantage to be derived from heating ofthe air in both cylinders.

We are aware that heaters have been employed in compoundsteam-enginesi'or heating the steam between the high and low pressurecylinders; butwemake no claim for steamengines. 7

We are also aware that compressed air has been heated beforeitsintroduction to an englue, and we therefore do not claim anythingrelating to such heating of the air but What we claim as our inventionis-,

The combination, with a compound engine for the use of compressed air asa motive power, of a heater, arranged-between the high and low pressurecylinders of such engine, and

"containing heated water or other liquid,

through or in direct contact with whichlth'e air passeson its way fromthe high-pressure to the low-pressure cylinder, substantially as and forthe purpose herein described.

eno. H. REYNOLDS; H. HAUPT.

Witnesses:

HENRY T. BRo'WNE,

FRED. HAYNES.

